How to set up custom tags

I have a question I hope someone can help me out with here

I want to set up some custom tags based on actions, I want to create tags for opens and clicks and create segments based on these values so my question is how would I do this, I see how to create the tag but unsure on creating the content to relate to the tag and how to generate the segments

Any help really appreciated guys


@David Henry - You define the tag in the list, but then this tag gets inherited by all subscribers so that's where it gets populated, either manually by subscribers, or by the app automatically when a campaign is sent and it is opened or a click inside is clicked, if you set this.
Later, you can create segments in that list, to only target subscribers whose custom fields have certain values.